Various types of amplifiers using active devices and reactance elements have been proposed as tuned amplifiers and are practically used for certain applications.
Disadvantages of such conventional tuned amplifiers include interaction between the tuned frequency and the maximum attenuation, i.e., an adjustment of the tuned frequency accompanies a change in the maximum attenuation and also an adjustment of the maximum attenuation accompanies a change in the tuned frequency.
Additionally, it is difficult to implement in an integrated circuit the tuned amplifier free from such interaction between the tuned frequency and the maximum attenuation.
It is, therefore, an object of the present invention to overcome the above-mentioned disadvantages of the conventional tuned amplifiers.